A range of personality types can find massive success in Silicon Valley.

There are power players like Uber cofounder and CEO Travis Kalanick known for being aggressive and outspoken, and those like Twitter cofounder and Medium founder and CEO Ev Williams known for working defensively and avoiding the spotlight.

Lowercase Capital investor Chris Sacca has worked closely with both Kalanick and Williams, as well as founders of other billion-dollar companies like Instagram, and has found that despite their differences, they all share one trait.

“And I don’t just mean in casual conversation,” Sacca says. “I mean these guys go out of their way to interview other people.”

Describing Williams, Sacca explains: “If you catch Ev, he’s got a notebook always. And if you ask him to see the last few pages of the notebook, he’s just meeting with other people — billionaires and leaders whose jobs might not overlap with his at all, but from whom he’s learning.”

As for Kalanick’s approach, Sacca says, “Travis would think it a competitive disadvantage for you to know exactly what’s going on in his head sometimes, so he’ll listen.”

Looking at all of his favourite entrepreneurs who have achieved growth with their companies, Sacca says, “These guys are learning, they’re modelling, they’re constantly researching, they’re gathering data.”

Sacca says entrepreneurs like Kalanick can seem like bullies because they listen more than they speak and only occasionally decide to unleash. “So when they do open their mouths, it can be bombastic and offensive and aggressive and in your face,” he says.

But whether they’re prone to crass jokes or quiet introspection, Sacca says, the best entrepreneurs are constantly learning and paying attention to everything around them.